| 摘要 |
A multijunction solar cell having at least four solar subcells includes a first solar subcell having a first band gap, and a first graded interlayer adjacent to the first solar subcell, wherein the first graded interlayer has a second band gap greater than the first band gap and that is constant at 1.5 eV throughout the thickness of the first graded interlayer. A second solar subcell is adjacent to the first graded interlayer, wherein the second solar subcell has a third band gap smaller than the first band gap of the first solar subcell and wherein said second solar subcell is lattice mismatched with respect to the first solar subcell. A second graded interlayer is adjacent to the second solar subcell, wherein the second graded interlayer has a fourth band gap greater than the third band gap of the second solar subcell and that is constant at 1.1 eV throughout the thickness of the second graded interlayer. A third solar subcell is adjacent to the second graded interlayer, wherein the third solar subcell has a fifth band gap smaller than the third band gap of the second solar subcell and wherein the third solar subcell is lattice mismatched with respect to the second solar subcell. Each of the first and second graded interlayers is composed, respectively, of a compositionally step-graded series of (InxGa1-x)yAl1-yAs layers with monotonically changing lattice constant, with x and y having respective values such that the band gap of each interlayer remains constant throughout its thickness, and wherein 0<x<1 and 0<y<1. |
